Scaling up a Dasher to WSSM or SAUM brass

[Romulus]

I've been messing with the idea of scaling up the Dasher to Short Action Magnum case specs using WSSM brass or SAUM brass.

The problem with the WSSM brass is that it is not possible achieve a scaled up version of a dasher in respect to case head diameter and then overall length without running out of brass.

I have not been frequenting the forums in the past few years due to my career taking most of my time so I do not know the gurus anymore in terms of Fireforming and calculating how far one can take a parent case.

If anyone has experience or an informed or calculable opinion on how far one can fireform a WSSM case heading towards a scaled up dasher I would greatly appreciate the input.

I have currently diagrammed 3 versions of a 25 WSSM improved (one easy to FF, one aggressive, and one that is not possible with WSSM parent case) and found that the fully scaled up Dasher would need to be made from SAUM brass and be much like a Sherman Short cartridge. With all that being said and the scaled Dasher being the target, I believe an improved WSSM will most likely fit the bill without going all the way to the original ideal of a Big Dasher.

Any experience with improved WSSM's, diagrams of such designs, or load data for 6, 257, and 6.5 WSSM or WSSM improved would be greatly appreciated.

 

[dkhunt14]

I dont know of any company producing good WSSM brass. I made a 6mm version and the brass (brand new never fired) was terrible. Some would fit the shellholder easy, some would be snug and some needed both thumbs to push them in. If the case heads vary that much, I don't know how you could get great accuracy.
I would use SAUM brass becuase you can get Norma. Matt

 

[mikecr]

I'm happy with 25wssm reloading brass(necked up to 26cal & neck turned). Thickness & weight variance by percentage is inline with Lapua, which is not as good as Norma, but wssm brass will last about six lifetimes longer than Norma.

I don't know what you think a scaled up 6Dasher would be.
You didn't declare the cal and bullet, which it would all begin with and center on.
And the diameter/length ratios are not what makes a Dasher right. It's the capacity.
The right capacity can be determined for other cals(given their best bullets),, they would end up nothing like a Dasher.

 

[Mulligan]

Tagging in
CW

 

[McFred]

I hear a lot about the quality of WSSM brass, but I have to wonder if any of reported experience is recent given it's been 15 years since the line came to market and the line's all but dead now. I've got a pile of Federal .223 WSSM brass from 2014 that has no issues in RCBS, Redding or Hornady shell holders. It's not Lapua brass, but it seems to do just fine when treated like most other brass (anneal, turn, size, trim, PP uniform, FH chamfer and weigh). I have seen recently that Hornady's producing brass for the WSSM line now, though I've heard no reports about its quality. I have seen new production Winchester on the LGS shelves too.

I have played with a 7mm WSSM wildcat driving 162-180gr projectiles with Reloder 17, H4350 and Superformance powders. 2800 fps is about the max with 180gr projectiles and net capacity hovers around 46-50 grains. Reloader 16 and one of the new Enduron IMR products might be about right too.

FWIW ESs and case life have benefited greatly from annealing the case necks, which are, admittedly, a little thick. I have one set of WIN brass that got more than 30 reloads before I had a case failure (split neck). So if you take the time to process the brass it should last you.

OP, I agree with mikecr about your objectives on a Dasher-like cartridge. Other than scaling, you don't mention what are you are trying to achieve. Improving the WSSM just makes an already overbore case moreso. The .223 version is ± equivalent to a .220 Swift Improved, the .243SSM is approx a .243 AI and the .25SSM is roughly equivalent to a .25-06. None I think are known for barrel life.

 

[Romulus]

I'm happy with 25wssm reloading brass(necked up to 26cal & neck turned). Thickness & weight variance by percentage is inline with Lapua, which is not as good as Norma, but wssm brass will last about six lifetimes longer than Norma.

I don't know what you think a scaled up 6Dasher would be.
You didn't declare the cal and bullet, which it would all begin with and center on.
And the diameter/length ratios are not what makes a Dasher right. It's the capacity.
The right capacity can be determined for other cals(given their best bullets),, they would end up nothing like a Dasher.

--

I understand your points but I have done plenty of math on three different trains of thought. Please provide your opinion of the best case capacity or dimensions for the class of projectile describe below.

To better fill you in, this project is to find great and then perhaps the best option to launch a 130-133 gr 0.257" bullet with a very high BC and low i7 / form factor - "Best" for my uses and most match shooters, a cartridge-bullet combination that will fit in a short action and allow the shooter to run the bullet from 2850-3100+ FPS even up to 3175 fps for certain prone style matches.

In some respects a 25x47 Lapua and 25 Creedmoor appear to be the best pragmatic candidates in terms of scaling power and easy parent cases, but in terms of scaling all dimensions since many believe the Dasher's geometry has some "magic" to it, only SAUM brass worked down short will do. In that line of thinking this short SAUM like a Sherman Short and a 25x284 Winchester will have within 3% case capacity.

My original chambering will be a 25x284 Win and be shot out of David Tubb's new Adaptive Target Rifle so I can push the projectiles as fast as practical in match use while being able to share BC data that will pair well with other standard cartridges launching the bullet 2800-3200 fps.

I will get to the 25-06 and 257 WBY later down the road - with this bullet they will really shine with very moderate recoil!

Please contact your barrel manufacturers and let them know they will need tooling for 1:7.25". I've got a handful on board and will be carrying at least 3 companies' barrel blanks on the website but ideally would want all the major shops to be ready to make fast twist 25 cal blanks.

 

[4xforfun]

300 WSM.....a scaled up Dasher.

6 Dasher next to a 6.5 WSSM
6 Dasher next to a 300 WSM

The WSSM case is to short to "scale up". It is basiclay the same length as the Dasher , but much fatter.

 

[Romulus]

View attachment 1044808 300 WSM.....a scaled up Dasher.

6 Dasher next to a 6.5 WSSM
6 Dasher next to a 300 WSM

The WSSM case is to short to "scale up". It is basiclay the same length as the Dasher , but much fatter.

--

Yes, the WSSM's are completely too short to blow out for a scaled dasher. the WSM's are also longer than a scaled dasher and more power than needed for 130 grain class bullets.

I know I will probably have to go 257 Sherman Short to chase the ideal, but I really want to know how far WSSM brass can be improved and still have a good neck on the case. I will chamber the 25 WSSM as-is to evaluate the performance just for a baseline and then do a secondary improved version just to see if it is viable and powerful enough.

 

[dmoran]

264/6.5 is only 8% larger then .243. Scaling a 6Dasher up 8% pretty much equals a 6.5x47.

To up scale it to magnum case diameter, is a 12% increase, making a 284/7mm at 15% larger, the closest marriage. Now pick a case with a body and shoulder length near 1.466" and you will have a 15% up-scaled Dasher.

 

[Romulus]

6.5/.264 is only 8% larger then .243. Scaling a 6Dasher up 8% pretty much equals a 6.5x47.

To up scale it to magnum case diameter, is a 12% increase, making a 284/7mm at 15% larger, the closest marriage. Now pick a case with a body and shoulder length near 1.466" and you will have a 15% up-scaled Dasher.

--

moran, can you show the math where the case capacity of a 6.5x284 is only 8% more voluminous than a 243 win? Or can you show the math you used for that 8% determination?

 

[dmoran]

.243 / .264 = 8%

Never said nothing about 6.5x284.
I said, scaling a 6Dasher up 8% pretty much equals a 6.5x47.

 

[Romulus]

.243 / .264 = 8%

Never said nothing about 6.5x284.
Scaling a 6Dasher up 8% pretty much equals a 6.5x47.

--

OK. I misread the 6.5/264 portion as 6.5x284.

I guess I don't immediately see your line of thinking comparing caliber diameters into percentages and how then you arrived at 1.466". Could you show your line of thinking more thoroughly and the associated math?

Taking a case head of 0.472" and scaling to 0.555 for WSSM changes the base-to-shoulder length of 0.472":1.196" to 0.555":1.406".

Given the slight difference of the SAUM case head (0.5512") it would be similar but 0.472":1.196" to 0.5512":1.396".

All of these differences are minute and the Sherman Short is the easiest method, but I wanted to see your line of thinking through from start to finish.

 

[dmoran]

To up scale evenly, as to mimic a 6Dasher closely, I suggest you do it by equal percentages in caliber.
Example:
.25-cal = 3%
264-cal = 8%
270-cal = 9%
284-cal = 15%
.30-cal = 19%
So if you want it to be a .264-cal, pick a case that is also 8% larger for a mother.... etc..

To get to magnum sized cases (.533 - .555), which are 12% to 15% larger in base then a Dasher, so should be the caliber, and is why I said: "a 7mm/284-caliber at 15% larger, is the closest marriage".
Next pick a case to make a body and shoulder length near 1.466", and you will have a 15% up-scaled Dasher.

In my opinion, a 300-WSM is the Dasher in magnums.

 

[TZaun]

Romulus I think you're onto something worth trying. I'm very curious to see how this turns out for you as I'm going to be trying something similar myself. I think the 25 WSSM case capacity will be near optimal for a bullet weight you describe. I'm trying a 6.5 WSSM Ackley right now and I can't quite push 155 gr. bullets as hard as I had hoped. I can just get them to a little over 2900 fps with H4831SC. I think I need to push them to around 2940 or so to get into the next node. Close but no cigar. They shoot really good at 2830 so that's where I'll run.

I agree with McFred about the bad rap WSSM brass received at the start. I've had a couple bags of early Winchester brass that was just like dkhunt experienced. I sure hope the new runs are made better than the first stuff. I found a bunch of Federal brass that has been very good for me. There is an outfit (can't remember the name) that will custom make WSSM brass in your desired caliber using Norma 300 WSM brass. I have 10 pieces of 300 WSSM in my possession. I would have to ask the guy that gave them to me, but I think they are around $3/piece. How's that for wishy-washy?

I wonder if a 25 WSSM would be overbore nearly as bad as the 25-06? It's so much more efficient and burning a lot less powder to get the same velocities should surely help with barrel life. I hope to find out first hand in a year shooting F-Class with it. Have fun with your project and let us know what you find.

 

[Loggins J]

I have a 6.5 WSSM AI you can get brass from hillbilly brass they will form it from any WSM brass I like mine I had a 6.5WSSM the problems is bolt thrust compressed loads you can get 3000 fps with 140 class bullets your slow powder will give you speed but compressed

 

[TZaun]

I have a 6.5 WSSM AI you can get brass from hillbilly brass they will form it from any WSM brass I like mine I had a 6.5WSSM the problems is bolt thrust compressed loads you can get 3000 fps with 140 class bullets your slow powder will give you speed but compressed

Yes, Hillbilly Brass. Thank you!!

I tried RL-16 but that pressured out at 2920 fps. The ladder I shot with it looked so messed up I didn't think it was worth pursuing any more. You're right though, H4831SC didn't show a single sign of pressure, I was into a compressed load before I could get up to my targeted velocity. I suppose I should try RL-17. Been dragging my feet because of the temperature instability. Something temp stable in between H4350 and H4831SC would be really nice.

 

[McFred]

I'm trying a 6.5 WSSM Ackley right now and I can't quite push 155 gr. bullets as hard as I had hoped. I can just get them to a little over 2900 fps with H4831SC

Look at Hodgdon's reload data RE .25 WSSM. The 120s are 160fps slower with H4831SC than with Superformance. H4350 and Hybrid 100V should yield more velocity than 4831. I'd wager that .007" bore diameter doesn't affect powders' velocity trends.

With RE-17 and H4350 I can get 2950 with 7mm 162s in a 27" barrel; 155gr should be cake.

*edit* reason: poor reading comprehension.

 

[TZaun]

I will have to try H4350 and RL-17 then. I didn't try H4350 because it sounds like it's near identical to RL-16 and that pressured out on me at 2920 (46.3 gr.). I have a .347" freebore on it, so I'm giving it a chance to get up there.

 

[mikecr]

Can you gain anything in 26cal with a 155gr bullet over 140gr? I wouldn't think so.
My 26wssm Imp has a 35deg shoulder, not full blown AI (yet). My mid node(which I've stayed with for several barrels) with 140gr bullets & 28" barrel is 3025fps using 47.4 IMR4350. ES =~8fps.
By QL this is right at 65Kpsi. No body sizing is ever needed with this(and my tight chamber). A higher node where body sizing would be required was found up at ~3190fps.
I had adjusted the design to match 260AI capacity, and it does.
You're welcome to compare that with a 6.5x284

Folks complain about brass for nearly all cartridges, but no matter how bad the available brass is, you can just pick out the diamonds. rake the rest into a trash can. I have over 50 reloads with ~80 or so diamonds in 25wssm, and it's apparent that they will last many more barrels over the rest of my life.
Now at my level of picky, it took over 750pcs to pull out ~120 with nearly no thickness variance, and given the thickness of new wssm cases, my percentage of variance here is better than I find in most lots of Lapua. These also weighed very close (again, impressive for this thickness). I turned the necks, and after deep body dip annealing and 3 fire formings, I measured my 80 keepers as matching in H20 capacity. They still match, as I don't have to re-trim brass (because I don't FL size).
Keep in mind that these cases -out of rubbish if chosen to generalize, are better than any cases you or I will ever buy and know, until we find and make them so.

The very best and the very worst lots I've ever measured were in Lapua brass(6br/223). The most consistently good measuring has been Norma(in 223). But it is also, always, the lowest in case life. Winchester reloading wssm brass is thick and hard. If you kill it, split necks or open pockets or whatever, you just don't know how to build and reload for the long run.

One last; Winchester should never have produced/released 22 & 24wssm. They should have went with 25 and 26wssm. They should have produced WSSM cases instead of forming them from WSM cases.
They should have adjusted WSSM guns for magnum tenons with coned breech. CRPF, standing blade ejection, and longer loading/ejection ports to clear very long bullets seated way out.
If all this had happened, people wouldn't be failing with and cursing WSSM.

 

[TZaun]

Good stuff Mike. It's almost a wash between the 140 Hybrid @ 3025 and the 155 Cauterucio @ 2940. There is a slight edge (2.73 MOA to 2.91 MOA in a 5 MPH missed wind call @ 1,000) to the 155. Since I can't get there (yet) like I had hoped, there's a big advantage to the 140 because you CAN get to 3025. I bought 1,000 of the 155s to shoot in my 6.5-284 but they wouldn't shoot in an 8-twist for me and I moved away from that cartridge when the barrel went. I know they'll shoot really good @ 2830 so I'll burn them up this summer, one way, or the other. I went all in with my super-long freebore and 7.25-twist.

How fast do you think a 25 WSSM Improved will be able to push a 110 gr. and a 135ish?